In the drilling, production, transport, storage, and processing of crude oil, including waste water associated with crude oil production, and in the storage of residual fuel oil, hydrogen sulfide and mercaptans are often encountered. The presence of hydrogen sulfide and mercaptans is objectionable because they often react with other hydrocarbons or fuel system components. Further, hydrogen sulfide and mercaptans are often highly corrosive as well as emit highly noxious odors. Uncontrolled emissions of hydrogen sulfide gives rise to severe health hazards. Burning of such vapors neither solves toxic gas problems nor is economical since light hydrocarbons have significant value.
Furthermore, hydrogen sulfide and mercaptans are often present in underground water removed with crude oil, in crude oil itself and in gases associated with such water and oil. When water and oil are separated from each other, they emit foul odors. For instance, hydrogen sulfide is emitted as a gas which is associated with water and hydrocarbon vapors. Natural gases further often contain hydrogen sulfide and mercaptans.
Treatments for removal of hydrogen sulfide and mercaptans from hydrocarbons and other substrates include the use of various reactive organic compounds. For example, U.S. Pat. No. 6,063,346 discloses the use of maleimides, formaldehydes, amines, carboxamides, alkylcarboxyl-azo compounds and cumine-peroxide compounds for the removal of hydrogen sulfide and mercaptans. Further, U.S. Pat. No. 5,128,049 discloses the use of certain morpholino and amino derivatives for the removal of hydrogen sulfide. In addition, U.S. Pat. Nos. 8,022,017; 7,264,786; 6,063,346 and 5,128,049 disclose the use of triazines to remove hydrogen sulfide.
Since the generation of hydrogen sulfide and mercaptans is often continuous throughout drilling, production, transport, storage and processing of crude oil as well as underground water, there is a need for the gradual and consistent release of hydrogen sulfide scavengers for removing such compounds.
It should be understood that the above-described discussion is provided for illustrative purposes only and is not intended to limit the scope or subject matter of the appended claims or those of any related patent application or patent. Thus, none of the appended claims or claims of any related application or patent should be limited by the above discussion or construed to address, include or exclude each or any of the above-cited features or disadvantages merely because of the mention thereof herein.